Journal of Machinery Manufacture and Reliability最新文献

The prospects for using microservice architecture in the development of flexible automated production control systems at mechanical engineering enterprises are considered. Methods for designing and implementing automated production control systems based on microservice architecture are discussed, and the advantages and disadvantages of this approach are shown. A prototype of a flexible automated system, developed using the Java language and the Spring framework, was proposed for the butt welding section of a metal disc production plant. The developed concept is a set of software modules in the form of microservices for independent data processing at each stage of the production process, which increases the fault tolerance and reliability of the entire system.

The problems of manufacturing low-stiffness parts for aircraft engineering, which have enormous advantages due to the implementation of power frame and skin elements in a single part, reduced labor intensity of processing and assembly, etc., are considered. A comparative analysis of methods for reducing residual stress is carried out, and the conclusion is reached that the most promising method for reducing residual stress is considered to be the one based on changing the cooling rate during the hardening process. General approaches to solving problems of residual stress control by the proposed method are formed based on consideration of isothermal decomposition diagrams. A ranked objective function for optimizing the quenching process to minimize the level of thermal residual stresses is presented, and boundary conditions for constructing possible technological processes for solving the optimization problem are determined.

In various industrial sectors, including energy, transportation, and other industries, a significant amount of diverse equipment operates, which is a system consisting of one, two, or bundles of pipes streamlined by liquids or gases. The flow of fluid passing through tube bundles, such as those in heat exchange equipment, causes them to vibrate. The efficiency of such pipeline systems largely depends on the correct design, installation, and operation.

This paper considers compressive thermomechanical loading and its effect on high-temperature strength characteristics of single-crystal SLZhS5-VI high-temperature nickel alloy. This treatment has been shown to considerably improve ductility (relative elongation and relative contraction) of the alloy at room and elevated temperatures and increase its time to rupture and creep resistance at a temperature of 900°C owing to the decrease in the density of casting defects (micropores and microcracks) as a result of the lower strain rate.

We have studied diamond-like carbon coatings produced by vacuum ion-plasma deposition. The coatings were doped with Ti ions via arc evaporation of a titanium cathode in parallel with laser arc evaporation of carbon from a graphite cathode. The titanium-doped diamond-like coatings were grown on 40CrNi steel substrates with a sorbite structure. The Ti content of the metal–carbon coatings thus prepared was in the range 1.5–5.5 wt %. The coating thickness was widely varied in our experiments, in the range δ = 0.5–4.5 μm. The effect of the parameter δ on tribological characteristics of the coatings was one of the key aspects of this research. The structure of the coatings was studied by high-resolution electron microscopy and their mechanical properties were studied using continuous indentation. The tribological properties of the coatings were assessed in ball-on-disk sliding friction tests on a tribometer at friction loads in the range F = 1–10 N. In analyzing the experimental data obtained, we used a computational analysis model which allowed us to construct critical state diagrams of various materials and coatings. The results demonstrate that such diagrams can be used for reliably predicting the minimum coating thickness δ_min needed for preventing premature failure of coatings in tribological tests. In addition, titanium doping of diamond-like carbon coatings (in the range of Ti concentrations studied) was shown to help stabilize the coating thickness: no spontaneous cracking of the coatings was detected at thicknesses of up to δ = 4.5 μm, and their microstructure remained sufficiently uniform, without any signs of formation of secondary carbide phases.

One of the peculiarities of bending tests of polymer fibrous composites is the need to use cylindrical supports of significant radius to avoid indentation and “nipping” of a sample with low transverse strength. In the refined formulation, a number of effects of the use of cylindrical supports are considered, the influence of which is strictly estimated by expansions in small parameters. The limits of deflection, sample sizes, and support radii are established, when, with a given accuracy, the specified effects can be neglected when determining Young’s modulus and the ultimate strength for normal and shear stresses. It is shown that when finding the interlayer shear modulus, the error that occurs when sample rolls off the supports can be significant; therefore, for the described method, the radius of the supports must be taken into account.

An approach to assigning rational machining modes for workpieces, based on the assessment of residual stresses, is considered. The advantages of the finite element modeling method for residual stresses arising during the cutting process are analyzed. The choice of the Johnson–Cook model, which describes the material deformation processes during machining, is substantiated. An analysis of the influence of technological parameters such as turning modes and the geometric parameters of a turning tool on the magnitude of residual stresses is carried out. An algorithm based on the finite element method, which allows for the assessment of residual stresses arising in workpieces during their turning, is presented.

Recently, the quality of equipment used in sugar beet production has been declining with continued operation, which is associated with the failure of key equipment components due to wear and exhaustion of their service life. An analysis of the performance of the technological equipment was conducted, identifying critically important units and assemblies that require restoration and reinforcement. Such measures will help reduce equipment downtime and increase its mean time between failures.

In this paper, the initial data for the controlled operation of locomotives are presented. The process of organizing and conducting the controlled operation of locomotive flange lubrication systems has been discussed and described. According to the developed scheme, three groups of 2ES6 electric locomotives operating on Russian railways have been selected for testing. Performance results from the controlled operation of the locomotive flange lubrication systems have been obtained. A graphical interpretation of the results of the controlled operation of locomotive flange lubrication systems has been developed. The average mileage between wheelset reprofiling operations, the average wheelset flange wear rate, and the average metal loss across the wheelset thread thickness for electric locomotives in operation across all three groups have been presented.

The modes of relative motion in three moving planes associated with the orbital station are considered: rectilinear separation and approach of tethered objects; hovering of the tethered object relative to the vertical equilibrium position; circular flight of the tethered object around the orbital station; separation of the tethered object from the orbital station upon approaching a rectilinear trajectory; approach of the tethered object to the orbital station with transition to a spiral trajectory; and revolution of the tethered object around the orbital station with simultaneous approach to/removal from the station. These modes exhibit the variety of possible maneuvers implementable using tether systems.